A substructure for an artificial lawn, comprising a top layer of artificial grass fibres and a substratum, which substratum comprises a number of individual layers, including a base layer, an intermediate layer positioned on top of said base layer and a sand layer positioned on top of said intermediate layer, wherein said sand layer comprises at least two sublayers, wherein the first sublayer comprises a sand fraction having a particle size which is larger than the particle size of the sand fraction of the second sublayer.
The present invention relates to a substructure for an artificial lawn, comprising a top layer of artificial grass fibres and a substratum positioned under said top layer, which substratum comprises a number of individual layers, including a base layer, an intermediate layer positioned on top of said base layer and a sand layer positioned on top of said intermediate layer.
Such a substructure is known per se from Dutch patent NL 1021171, in which an artificial lawn is made up of a relatively hard base layer, on which a flat layer of a resilient and/or damping material is arranged, which layer may have a thickness of about 6-35 mm, for example 10-14 mm. Arranged on top of said resilient and/or damping layer is a top layer in the form of a synthetic turf consisting of a backing layer and artificial grass stalks attached thereto by tufting, knitting or weaving. The resilient and/or damping layer may be formed in various ways, for example by starting from a mixture of rubber granules mixed with a liquid binder, for example polyurethane.
A substructure for playing golf is known per se from British patent publication GB 2 072 022.
International application WO 2006/007862 further discloses a base for a sports floor.
From Dutch patent No. 1013987 there is furthermore known a base provided on a foundation layer for a sports field that is at least partially covered with grass, which base partially consists of rock wool.
Dutch patent No. 1016193 discloses an artificial lawn comprising a drainage layer made up of pebbles, a base layer arranged on top of said drainage layer, which base layer comprises the originally dug-off and subsequently removed soil, and a top layer with fibres present therein.
From European application EP 1 428 935 there is known a substructure for an artificial lawn in which a so-called “undersheet” of a geotextile material is laid over a prepared base, on which undersheet a layer of sand is arranged, on which subsequently a layer of rubber and finally a textile web are laid so as to thus form a so-called “envelope”. The undersheet and the textile web are bonded together at their margins. Finally, an artificial lawn is installed on said substructure.
European application EP 0 093 008 discloses a base on which an envelope of a particular fabric is arranged, which envelope is filled with sand, for example, a base layer comprising a sheet of bound rubber particles, on which base layer an artificial lawn or a polyethylene foam layer can be laid. Depending on the sport to be practised, different sand grain sizes are used.
European application EP 1 462 572 relates to a substructure for sports floors, comprising a sand package provided with a water distribution system, which system comprises distribution pipes connected to a water reservoir.
Artificial lawns are generally used for a large number of sports, for example soccer and field hockey. If an artificial lawn is used for playing field hockey, it is advisable to water the lawn before it is used. Generally, use is made of a sprinkler installation in such a situation, by means of which a layer of water is applied to the lawn in a short time via a number of sprinkler points. In practice it has been found, however, that a large part of the water evaporates in a natural way or is carried off by the wind without ever reaching the lawn in question. In addition to that, very large quantities of water are used for “inundating” an artificial lawn, which is found to be objectionable in practice both for environmental and for economic reasons.